3168 - Minimum Number of Chairs in a Waiting Room.

Easy

You are given a string s. Simulate events at each second i:

• If s[i] == 'E', a person enters the waiting room and takes one of the chairs in it.

• If s[i] == 'L', a person leaves the waiting room, freeing up a chair.

Return the minimum number of chairs needed so that a chair is available for every person who enters the waiting room given that it is initially empty.

Example 1:

Input: s = "EEEEEEE"

Output: 7

Explanation:

After each second, a person enters the waiting room and no person leaves it. Therefore, a minimum of 7 chairs is needed.

Example 2:

Input: s = "ELELEEL"

Output: 2

Explanation:

Let's consider that there are 2 chairs in the waiting room. The table below shows the state of the waiting room at each second.

Example 3:

Input: s = "ELEELEELLL"

Output: 3

Explanation:

Let's consider that there are 3 chairs in the waiting room. The table below shows the state of the waiting room at each second.

Constraints:

• 1 <= s.length <= 50

• s consists only of the letters 'E' and 'L'.

• s represents a valid sequence of entries and exits.